Exercise Four. Primary Colours.

Start Photoshop and create a new document with the following properties :-

Name : ‘Ex 3 – Primary Colours’

Size : A4 @ 300dpi

Colour Mode : RGB / 8 bpc

Background Colour : White

What is the keyboard shortcut for creating a new Document ? Command N 

What is the size of the image in :-

Megapixels _______      Megabytes 

Set the foreground colour to Red (ie R 255, G 0, B 0).

Select the Ellipse Tool (not the Marquee tool). What is the keyboard shortcut :- U

Draw a circle with the Ellipse tool approximately 6cm in diameter (about 1/3^rd of the page width) – display the rulers and use Preferences to set the units to cm .

Which key forces the ellipse to be a circle ? SHIFT

Change the layer name to ‘Red Circle’.

Duplicate the layer and 

change the colour to green and 

change the name to ‘Green Circle’. 

Note: To change the colour click on the colour button on the option bar immediately after duplicating the layer, or double click on the layer in the Layers palette.

Duplicate this layer and 

change the colour to blue and 

change the name to ‘Blue Circle’.

Select the Move tool. What is the keyboard shortcut ?   V

Turn on the ‘Auto-select’ option.

Spread the three circles across the top of the page with a small space above them (they may overlap a bit – that’s OK).

Fit the image to the screen (ie so the whole page is visible)

What is the keyboard shortcut for this ? Command Plus

Go to Full Screen Mode – ‘View -> Screen Mode ->Full Screen Mode’.

What is the keyboard shortcut ? F

Stare at the centre of the middle circle for 20 seconds, then look at the white area below. You will see an after image.

What colour are the after images for each circle ?

Red - Yellow (I have no idea if this is working but this is what I see!)

Green - RED

Blue - Not really a colour just a white/yellow circle

Select all three layers in the layers palette.

Group the three layers together by selecting ‘Layer -> Group’.

What is the keyboard shortcut ? Command G

Select the group in the layers palette containing the three circles.

Change the ‘Blending Mode’ for the group from ‘Pass Through’ to ‘Difference’. (We will be looking at Blending Modes later, so don’t worry if you don’t understand them now).

Stare at the centre of the middle circle for 20 seconds, then look at the white area below. You will see an after image.

What colour are the after images for each circle?

Cyan - RED

Magenta - GREENISH

Yellow - Same here - I don't ready get an after      colour but I am guessing its bluish! 

Save the document as ‘Ex 3 – Colour Theory.psd’

What is the size of the .psd file on disk ? 1.1 MB 

How does this compare to the image size you recorded in step 3 above.